Units and syringes
How many units is 0.1 mL?
10 units on a U-100 insulin syringe. Each unit is 0.01 mL.
What does U-100 mean?
The syringe is marked for 100 units per mL. It is the standard for insulin syringes in the United States. U-40 syringes are marked differently and are not covered by these calculators.
Which syringe size should I use?
The smallest one that holds your dose: 0.3 mL for up to 30 units, 0.5 mL for up to 50, 1 mL for up to 100. Smaller syringes have more widely spaced markings, which makes them easier to read.
Concentration and mixing
What is concentration?
How much of the substance is in each mL of liquid. It equals the amount in the vial divided by the volume of liquid added, for example 5 mg ÷ 2 mL = 2.5 mg/mL.
Does adding more water change the dose?
It does not change how much is in the vial, but it changes how many units hold a given dose. More water means more units for the same dose. Recalculate whenever the water volume changes.
What is bacteriostatic water?
Sterile water with 0.9% benzyl alcohol, a preservative that slows bacterial growth in multi-use vials.
mg or mcg?
1 mg = 1,000 mcg. Always check which unit your vial label and your instructions use.
About the calculators
Are the results guaranteed to be correct?
The formulas are standard and shown on every page, but results are only as good as the numbers entered. Double-check everything with your pharmacist or prescriber.
Do you store what I type?
No. The calculations happen in your browser. If you use "Copy link", your numbers are included in that link.
Can you tell me what dose to take?
No. We only convert numbers. Dosing must come from a licensed healthcare professional or the product documentation.